Risk Factors for Correction Loss of Vertebral Slippage after Minimally Invasive Transforaminal Lumbar Interbody...

Some cases of postoperative correction loss have been observed in the reduction of vertebral slippage using a percutaneous pedicle screw system for lumbar degenerative spondylolisthesis. We aimed to identify the risk factors for correction loss after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and to determine the effect of postoperative correction loss on postoperative clinical outcomes.

In this retrospective study, a total of 111 patients (mean age 69.5 years, 37 men and 74 women) who underwent single-level MIS-TLIF with slippage reduction for lumbar degenerative spondylolisthesis and were followed up for >1 year were included in the study. The correction loss group (group L) included those with a correction loss of ≥3 mm between immediately after surgery and 1 year after surgery, and the correction maintenance group (group M) included those with a correction loss <3 mm. Demographic data, preoperative and postoperative radiographic measurements, and clinical outcomes were collected, and the risk factors in group L and clinical outcomes in the two groups were analyzed statistically.

Groups L and M comprised 19 and 92 cases, respectively. High pelvic incidence-lumbar lordosis (odds ratio [OR]: 1.16, 95% confidence interval [CI]: 1.07-1.25, p<0.001), high slip vertebra slope (OR: 1.22, 95% CI: 1.07-1.39, p<0.001), and ≥10° segmental angulation (OR: 15.00, 95% CI: 3.04-73.95, p=0.0022) were risk factors for correction loss; however, low bone density was not. The Oswestry Disability Index and Visual Analog Scale scores for low back pain, leg pain, and leg numbness were not significantly different between both groups; however, the bone union rate at 6 months postoperatively was significantly lower in group L (p=0.0020).

Postoperative correction loss was influenced by preoperative sagittal alignment and instability rather than bone density. Patients with correction loss tend to have prolonged bone union and should be closely monitored.